JP5820435B2 - Method for reinforcing steel structure and elastic layer forming material for reinforcing steel structure - Google Patents

Description

The present invention uses a sheet-like reinforcing fiber-containing material containing continuous reinforcing fibers (hereinafter referred to as “fiber sheet”), and is used for steels such as bridges, piers, chimneys, and ships, vehicles, and aircraft. structure repair reinforcement (hereinafter, simply "reinforcement" hereinafter.) relates to an elastic layer forming material of the reinforcing method及beauty steel structure for reinforcement of steel structures.

  In recent years, carbon fiber sheet bonding method or aramid fiber sheet bonding method in which continuous reinforcing fiber sheet such as carbon fiber sheet or aramid fiber sheet is pasted or wound on the surface as a reinforcing method of existing or new steel structure There is a continuous fiber sheet bonding method. Further, there is a method of curing after bonding a fiber sheet in which a continuous fiber bundle is impregnated with an uncured matrix resin.

  Furthermore, in order to omit the impregnation of the resin on site, an FRP plate adhesion reinforcing method has been developed in which a factory-produced FRP plate having a thickness of 1 to 2 mm and a width of about 5 cm is adhered using a putty-like adhesive resin.

  The steel structure reinforced by such a method can obtain a high reinforcing effect by the fiber sheet as long as the fiber sheet is integrally bonded to the steel structure. However, if the steel sheet is peeled off from the surface of the steel structure before the fiber sheet breaks due to deformation of the steel structure due to the load, the intended purpose cannot be achieved.

Therefore, Patent Document 1 discloses a method of providing a buffer material layer on the surface of a steel structure and then bonding and reinforcing the fiber sheet with an adhesive. Moreover, it discloses that a resin such as a thermosetting resin or a thermoplastic resin can be used as the buffer material layer. In addition, it is disclosed that the tensile elastic modulus at 23 ° C. when this resin is cured alone is 0.1 to 50 N / mm ² .

Japanese Patent No. 3553865

  However, as a result of our research experiments, the problem that the fiber sheet peels off the surface of the steel structure when reinforcing the steel structure is different from the case of reinforcing the concrete structure with the fiber sheet. It has been newly found that the temperature of the is greatly affected. Therefore, when reinforcing a steel structure with a fiber sheet, it is necessary to fully consider the temperature of the steel structure surface. Steel structures (steel materials) have a greater elongation due to temperature and deflection due to vehicle traffic than concrete structures. Therefore, when a continuous fiber sheet having high rigidity is bonded to the steel structure, there is a concern that the fiber sheet peels from the end portion.

  Here, for example, in Japan, the surface of a steel structure is known to rise to a temperature of about 60 ° C. by direct sunlight in midsummer. For this reason, it has been found that when an adhesive or the like used for reinforcement by a conventional fiber sheet is used, the adhesive softens due to its high surface temperature, and sometimes the necessary reinforcing effect may not be obtained.

  Moreover, in the reinforcement method of the said patent document 1, when the tensile elasticity modulus of resin which forms a buffer material layer is low, and it reinforces with a rigid continuous fiber sheet etc., the stress which a buffer material layer should be transmitted to a fiber sheet originally May not be transmitted. That is, in this case, the fiber sheet is not useful and cannot be reinforced.

Therefore, the purpose of the present invention is to avoid a situation where the reinforcing effect by the fiber sheet cannot be obtained by irradiation with sunlight, etc. when the steel structure is reinforced with the fiber sheet, and a sufficient reinforcing effect can be obtained. and to provide a reinforcing method及beauty steel structure reinforcing elastic layer forming material of steel structures that can be fibrous sheet to prevent the peeling off from the steel structure surface before rupture.

The above object is achieved by a steel structure reinforcing method and a steel structure reinforcing elastic layer forming material according to the present invention. In summary, according to the first aspect of the present invention, in a method for reinforcing a steel structure in which a fiber sheet containing reinforcing fibers is bonded and integrated on the surface of the steel structure,
(A) applying a polyurea resin putty agent to the surface of the steel structure and curing it to form an elastic layer;
(B) the said fiber sheet to the surface of the steel structures elastic layer is formed, possess a step of bonding, a by an adhesive,
The polyurea resin putty agent has a tensile elongation at curing of 400% or more, a tensile strength of 8 N / mm ² or more, and a tensile modulus of 60 N / mm ² or more and 500 N / mm ² or less,
The adhesive has a glass transition temperature of 60 ° C. or higher.
A method for reinforcing a steel structure is provided.

According to another embodiment of the first invention, the adhesive used in the step (b) is a room temperature curing type epoxy resin, epoxy acrylate resin, acrylic resin, MMA resin, vinyl ester resin, unsaturated polyester. It is a resin or a photocurable resin .

  According to another embodiment of the first aspect of the present invention, before forming the elastic layer on the surface of the steel structure, the step of applying a primer to the surface of the steel structure and / or the step of applying a primer, Have

  According to another embodiment of the first aspect of the present invention, the fiber sheet is a fiber sheet in which continuous reinforcing fibers aligned in one direction are fixed to each other with a wire fixing material. Alternatively, the fiber sheet is a fiber sheet in which reinforcing fibers are impregnated with a matrix resin, a plurality of cured continuous fiber reinforced plastic wire materials are arranged in a slender shape in the longitudinal direction, and the wire materials are fixed to each other with a wire material fixing material. It is. Alternatively, the fiber sheet is a fiber sheet in which a continuous reinforcing fiber sheet aligned in one direction is impregnated with a resin and the resin is cured.

  According to another embodiment of the first aspect of the present invention, the fiber sheet is laminated and bonded to the surface of the steel structure in a plurality of layers, and is integrated with the steel structure.

According to the second invention,
A method of reinforcing a steel structure in which a fiber sheet containing reinforcing fibers is bonded and integrated on the surface of the steel structure,
(A) applying a polyurea resin putty agent to the surface of the steel structure and curing it to form an elastic layer;
(B) bonding the fiber sheet to the surface of the steel structure on which the elastic layer is formed, using an adhesive;
A steel structures reinforcing the elastic layer forming material made of polyurea resin putty agent to form a pre-Symbol elastic layer Te reinforcing method smell steel structures having,
The polyurea resin putty agent has a tensile elongation at curing of 400% or more, a tensile strength of 8 N / mm ² or more, and a tensile modulus of 60 N / mm ² or more and 500 N / mm ² or less. A reinforcing elastic layer forming material is provided.

According to the reinforcing method及beauty steel structure reinforcing elastic layer forming material of the steel structure of the present invention to avoid becomes such a situation not be obtained reinforcing effect by the irradiation sunlight, it is possible to obtain a sufficient reinforcing effect, And it can avoid that a fiber sheet peels off from the steel structure surface before reaching a breaking strength.

FIG. 1 is a cross-sectional view of an example of a reinforced steel structure for explaining a steel structure reinforcing method and a reinforcing structure according to the present invention. FIG. 2 is a view showing an embodiment of a fiber sheet that can be used in the steel structure reinforcing method of the present invention. FIG. 3 is a view showing another embodiment of a fiber sheet that can be used in the steel structure reinforcing method of the present invention. FIG. 4 is a perspective view showing an embodiment of a fiber sheet that can be used in the steel structure reinforcing method of the present invention. FIG. 5 is a cross-sectional view of an example of a fiber-reinforced plastic wire constituting a fiber sheet that can be used in the steel structure reinforcing method of the present invention. FIG. 6 is a perspective view showing another embodiment of a fiber sheet that can be used in the steel structure reinforcing method of the present invention. FIG. 7 is a process diagram for explaining an embodiment of the steel structure reinforcing method of the present invention. FIG. 8 is a process diagram for explaining another embodiment of the steel structure reinforcing method of the present invention. FIG. 9 is a diagram illustrating the configuration of a bending strength test apparatus for demonstrating the steel structure reinforcing method of the present invention. FIG. 10 is a diagram showing a bending test result of a steel structure reinforced in accordance with the present invention. FIG. 11 is a diagram showing a bending test result of a reinforced steel structure for comparing the present invention with a comparative example. FIG. 12 is a diagram showing a bending test result of a reinforced steel structure for comparing the present invention with a comparative example.

Hereinafter will be described in more detail with reference to reinforcing method及beauty steel structure reinforcing elastic layer forming material of the steel structure according to the present invention with reference to the drawings.

  Referring to FIG. 1, according to the method for reinforcing a steel structure according to the present invention, a steel sheet 100 is bonded to a fiber sheet 1 including continuous reinforcing fibers f on the surface thereof through an elastic layer 104. Integrated.

The feature of the steel structure reinforcing method of the present invention is:
(A) applying a polyurea resin putty agent to the surface 102 of the steel structure 100 and curing it to form an elastic layer 104 as a buffer layer;
(B) The fiber sheet 1 is bonded to the surface of the steel structure 100 on which the elastic layer 104 is formed, using an adhesive 105 adjusted so that the glass transition temperature is 60 ° C. or higher as necessary. Process,
It is in the composition which has.

That is, according to the present invention,
(A) an elastic layer 104 formed by applying a polyurea resin putty agent to the surface 102 of the steel structure 100;
(B) a resin-impregnated fiber sheet layer 106 adhered by an adhesive 105 to the surface 102 of the steel structure 100 on which the elastic layer 104 is formed;
A reinforcing structure for a steel structure is provided. The elastic layer 104 has a tensile elongation at curing of 400% or more, a tensile strength of 8 N / mm ² or more, and a tensile modulus of 60 N / mm ² or more and 500 N / mm ² or less.

  According to the present invention, preferably, the surface 102 of the steel structure 1 can be pretreated before the elastic layer 104 is formed on the surface of the steel structure 100, and further, the primer is applied to the surface 102 of the steel structure. Apply.

  Next, each material used in the present invention will be described.

(Fiber sheet)
In the present invention, various forms of fiber sheets 1 can be used. Although the Example of the fiber sheet 1 is concretely demonstrated as the specific examples 1-3, the form of the fiber sheet 1 used by this invention is not limited to what is shown to these specific examples.

Example 1
FIG. 2 shows an embodiment of the fiber sheet 1 that can be used in the present invention. The fiber sheet 1 is a non-resin-impregnated fiber sheet 1A configured in a sheet shape by aligning continuous reinforcing fibers f in one direction.

That is, 1 A of fiber sheets can be set as the structure which hold | maintained the reinforcing fiber sheet which consists of the continuous reinforcing fiber f arranged in one direction with the wire fixing material 3 used as a mesh-like support body sheet | seat. For example, when carbon fibers are used as the reinforcing fibers f, for example, a plurality of unimpregnated single fiber bundles in which 6000 to 24000 single fibers (carbon fiber monofilaments) f having an average diameter of 7 μm are converged in parallel in one direction. Used to align. The fiber basis weight of the carbon fiber sheet 1A is usually 30 to 1000 g / m ² .

  Carbon obtained by impregnating the surfaces of the warp yarn 4 and the weft yarn 5 constituting the mesh-like support sheet as the wire fixing material 3 in advance with a low melting point type thermoplastic resin, and arranging the mesh-like support sheet 3 in a sheet shape The fibers are laminated on one or both sides of the fiber and heated and pressed to weld the warp 4 and weft 5 portions of the mesh-like support sheet 3 to the carbon fiber sheet.

  In addition to the biaxial configuration, the mesh-shaped support sheet 3 is formed by orienting glass fibers in three axes, or only the wefts 5 orthogonal to the carbon fibers arranged in one direction. It can also be bonded to the so-called uniaxially oriented carbon fibers that are arranged and aligned in the form of a sheet.

  As the yarn of the wire fixing material 3, for example, a double-structured composite fiber having a glass fiber in the core and a low-melting-point heat-fusible polyester around it is also preferably used. .

Example 2
Further, as shown in FIG. 3, the fiber sheet 1 is obtained by impregnating a resin fiber Re with a reinforcing fiber sheet in which a plurality of reinforcing fibers f are aligned in one direction, for example, a fiber sheet 1A as shown in FIG. A fiber sheet (so-called FRP plate) 1B in which is cured.

  In the fiber sheets 1A and 1B described in the specific examples 1 and 2, the reinforcing fiber f is not limited to carbon fiber, but glass fiber, basalt fiber; metal fiber such as boron fiber, titanium fiber, and steel fiber. Further, organic fibers such as aramid, PBO (polyparaphenylene benzbisoxazole), polyamide, polyarylate, and polyester can be used singly or in a mixture of plural kinds.

  In addition, as the resin Re in the case of the fiber sheet 1B in the specific example 2, a thermosetting resin or a thermoplastic resin can be used. As the thermosetting resin, a room temperature curing type or a thermosetting type epoxy resin can be used. Vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, phenol resin and the like are preferably used, and nylon, vinylon and the like can be suitably used as the thermoplastic resin. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

Example 3
Further, as shown in FIGS. 4 and 5, the fiber sheet 1 has a plurality of continuous fiber reinforced plastic wires 2 having a small diameter, which are impregnated with the matrix resin R and cured, and are arranged in a slender shape in the longitudinal direction. Moreover, the fiber sheet 1C which fixed each wire 2 with the wire fixing material 3 mutually can also be used.

  The fiber reinforced plastic wire 2 has a substantially circular cross-sectional shape (FIG. 5A) having a diameter (d) of 0.5 to 3 mm, or a width (w) of 1 to 10 mm and a thickness (t) of 0. A substantially rectangular cross-sectional shape (FIG. 5B) of 1 to 2 mm can be obtained. Of course, other various cross-sectional shapes can be used as necessary.

  As described above, in the fiber sheet 1 that is aligned and slid in one direction, the wires 2 are close to and separated from each other by a gap (g) = 0.05 to 3.0 mm. Fixed. In addition, the length (L) and width (W) of the fiber sheet 1 formed in this way are appropriately determined according to the size and shape of the structure to be reinforced, The total width (W) is 100 to 1000 mm. Moreover, although the length (L) can manufacture a strip-shaped thing about 1-5 m, or a thing 100 m or more, it cuts and uses it suitably at the time of use.

  It is also possible to manufacture the fiber sheet 1C with a length (L) of about 1 to 5 m and a width W of about 1 to 10 m longer than this.

  Even in the case of the fiber sheet 1C, as the reinforcing fiber f, carbon fiber, glass fiber, basalt fiber; metal fiber such as boron fiber, titanium fiber, steel fiber; and aramid, PBO (polyparaphenylene benzbisoxazole) Organic fibers such as polyamide, polyarylate, and polyester can be used alone or in a mixture of plural kinds. The matrix resin R impregnated in the fiber reinforced plastic wire 2 can be a thermosetting resin or a thermoplastic resin. As the thermosetting resin, a room temperature curing type or a thermosetting type epoxy resin, A vinyl ester resin, an MMA resin, an acrylic resin, an unsaturated polyester resin, a phenol resin, or the like is preferably used, and nylon, vinylon, or the like can be preferably used as the thermoplastic resin. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

  Further, as a method of fixing each wire 2 with the wire fixing material 3, for example, as shown in FIG. 4, a plurality of wires arranged in a sag-like manner using wefts as the wire fixing material 3 are arranged. It is possible to adopt a method of driving and knitting a wire rod in the form of a sheet consisting of two, that is, a continuous wire rod sheet at a constant interval (P) perpendicular to the wire rod. The driving interval (P) of the weft yarn 3 is not particularly limited, but is usually selected in the range of 10 to 100 mm in consideration of the handleability of the produced fiber sheet 1.

  At this time, the weft 3 is, for example, a yarn obtained by bundling a plurality of glass fibers or organic fibers having a diameter of 2 to 50 μm. Moreover, nylon, vinylon, etc. are used suitably as an organic fiber.

  As another method of fixing each wire 2 in a slender shape, a mesh-like support sheet can be used as the wire fixing member 3 as shown in FIG.

  That is, the above-mentioned specific example in which a plurality of wire rods 2 arranged in the form of a sheet in a sheet form, that is, one side or both sides of a wire sheet is made of glass fiber or organic fiber having a diameter of 2 to 50 μm, for example. 1 may be configured to be supported by a mesh-like support sheet 3 having the same configuration as described in 1.

  Furthermore, as another method of fixing each wire 2 in a slender shape, as shown in FIG. 6 (b), as the wire fixing material 3, for example, a flexible belt material such as an adhesive tape or an adhesive tape is used. Can be used. The flexible strip 3 has one side or both sides of a plurality of fiber reinforced plastic wires 2 in a direction perpendicular to the longitudinal direction of each fiber reinforced plastic wire 2 arranged in the form of a sheet. Paste and fix.

  That is, as the flexible strip 3, an adhesive tape or adhesive tape such as a vinyl chloride tape, a paper tape, a cloth tape, and a nonwoven fabric tape having a width (w1) of about 2 to 30 mm is used. These tapes 3 are usually stuck in a direction perpendicular to the longitudinal direction of each fiber reinforced plastic wire 2 at intervals (P) of 10 to 100 mm.

  Furthermore, as the flexible strip 3, the thermoplastic resin such as nylon or EVA resin is formed into a strip and is heat-bonded to one side or both sides in the direction perpendicular to the longitudinal direction of the wire 2. Is done.

(Reinforcing method)
Next, a method for reinforcing a steel structure will be described with reference to FIG. According to the present invention, the steel structure is reinforced using the fiber sheet 1 manufactured as described above.

  That is, according to the method for reinforcing a steel structure of the present invention, for example, as the fiber sheet 1, the fiber sheet 1A produced by aligning the reinforcing fibers f described in the specific example 1 in one direction can be used. The adhesive layer 105 is bonded and integrated on the elastic layer 104 formed on the surface of the steel structure. At this time, simultaneously with the adhesion of the fiber sheet 1A to the steel structure, the adhesive (matrix resin) impregnation of the fiber sheet 1A with this adhesive can also be performed.

  Thereby, the reinforcing structure 200 of the steel structure having the elastic layer 104 and the fiber sheet layer 106 to which the fiber sheet 1 impregnated with the resin is bonded is formed.

  When reinforcing the steel structure 100, for members (structures) that mainly receive bending moment and axial force, the orientation direction of the reinforcing fibers is generally aligned with the principal stress direction of tensile stress or compression stress generated by the bending moment. By bonding, it is possible for the fiber sheet 1 to effectively bear the stress and to efficiently improve the load resistance of the structure.

  When bending moments act in two orthogonal directions, two or more fiber sheets 1 are orthogonally laminated and bonded so that the orientation direction of the reinforcing fibers f of the fiber sheet 1 substantially coincides with the principal stress generated by the bending moment. By doing so, the load bearing capacity can be improved efficiently.

(First step)
As shown in FIGS. 7 (a) and 7 (b), if necessary, the weakened portion 101a of the surface to be reinforced (that is, the surface to be bonded) 101 of the steel structure 100 is replaced with a disk sander, sandblast, steel shot blast, It removes by the grinding means 50, such as a water jet, and the to-be-adhered surface 101 of the steel structure 100 is surface-treated.

(Second step)
An epoxy-modified urethane resin primer 103 is applied to the surface 102 subjected to the ground treatment (FIG. 7C). The primer 103 is appropriately selected according to the material of the elastic layer 104 (FIG. 7D) and the reinforced steel structure 100, such as an MMA resin, without being limited to the epoxy-modified urethane resin.

  In addition, the application | coating process of the primer 103 can also be skipped.

(Third step)
A polyurea resin putty agent 104 is applied to the ground-treated surface 102 at a required thickness (T) and cured to form an elastic layer 104 (FIG. 7D). The coating thickness (T) is appropriately set according to the unevenness on the surface of the adherend surface 102 and the thickness T of the fiber sheet 1, but is generally about T = 0.2 to 10 mm.

In the present invention, the polyurea resin putty agent having a low elastic modulus, that is, the material forming the elastic layer 104 (elastic layer forming material) contains a main agent, a curing agent, a filler, an additive, etc. An example is as follows.
(I) Main agent: A prepolymer having an isocyanate (for example, 4, -4′diphenylmethane diisocyanate) as a reaction component and having a terminal residual isocyanate adjusted to 1 to 16 parts by weight with NCO wt%.
(Ii) Curing agent: A curing agent containing an aromatic amine (for example, an amine value of 80 to 90) is used as a main component, and the NCO: amine ratio of the main agent is calculated at 1.0: 0.55 to 0.99 parts by weight. Use what was done. Furthermore, p-toluenesulfonic acid salt etc. can also be included as a hardening accelerator.
(Iii) Filler: Meteorite powder, a habit modifier, and the like are included, and are appropriately blended in an amount of 1 to 500 parts by weight.
(Iv) Additives: Colorants, viscosity modifiers, plasticizers and the like are included, and are appropriately blended in an amount of 1 to 50 parts by weight.

Here, the polyurea resin putty agent has a tensile elongation at curing of 400% or more (usually 400 to 600%), a tensile strength of 8 N / mm ² or more (usually 8 to 10 N / mm ² ), and a tensile elastic modulus. 60 N / mm ² or more and 500 N / mm ² or less (usually 60 to 100 N / mm ² ).

If the elastic modulus is less than 60 N / mm ² , the necessary reinforcing stress cannot be transmitted, and conversely, if it exceeds 100 N / mm ² , particularly if it exceeds 500 N / mm ² , the problem of insufficient elongation performance arises. .

  Moreover, in order to use polyurea resin as a putty agent, the viscosity at 2 revolutions by a BM type viscometer at 23 ° C. is 200 to 700 Pa · s, and at 20 revolutions, it is in the range of 60 to 100 Pa · s. It is desirable that the thixotropic index, that is, the ratio of the measured values of viscosity at different rotational speeds by a rotational viscometer (viscosity at 20 rotational speeds ÷ viscosity at 2 rotational speeds) is 4 to 7.

  That is, when the viscosity is less than 60 Pa · s and the thixotropic index is less than 4, sagging occurs after coating, and it becomes difficult to apply the smoothness of the coated surface and the ceiling surface and wall surface, and conversely, the viscosity is 100 Pa. If the thixotropic index is larger than s and exceeds 7, the resin is hard, there is a problem in mixing, and it is difficult to apply smoothly.

  Here, Table 1 below shows the epoxy resin putty agent conventionally used as the material for forming the buffer material layer described in Patent Document 1 and the material for forming the elastic layer used in the present invention. The result of having compared the physical property which the polyurea resin putty agent of the said composition has is shown.

  From the results of Table 1 above and the relationship between the temperature and elastic modulus of the buffer layer (Table 2 above), when an epoxy resin putty agent is used, elongation and toughness cannot coexist, especially at high temperatures. The material strength of the epoxy resin is reduced and the steel material reinforcing effect cannot be exhibited. In addition, when the temperature is low in winter, the elongation is extremely deteriorated and becomes hard, leading to early peeling.

  On the other hand, the polyurea resin putty agent used in the present invention can exhibit stable performance from −20 ° C. to + 70 ° C. Therefore, the polyurea resin putty agent can be used as an elastic layer forming material for reinforcing steel structures, and can achieve peeling prevention and repair reinforcement effects that are not affected by temperature, and is extremely suitably used for the reinforcement method of steel structures. I knew I would get it.

(4th process)
As shown in FIGS. 7E and 7F, when the resin putty is cured and the elastic layer 104 is formed, an adhesive 105 is applied on the elastic layer 104, and a fiber sheet is applied to this surface. 1 pressed adhered via an elastic layer 104 on the surface 102 of the reinforcing target steel structure 100.

  As the adhesive 105, an adhesive whose glass transition temperature is adjusted to 60 ° C. or higher, usually 70 ° C. to 100 ° C., is preferably used for application at high temperatures. As described above, the surface of the steel structure 100, that is, the steel material, rises to a temperature of about 60 ° C. in Japan due to direct sunlight in midsummer. For this reason, it has been found that the adhesive used for the reinforcement with the fiber sheet of the conventional specification softens depending on the temperature, and sometimes the necessary repair and reinforcement effect may not be obtained.

  Therefore, by using an adhesive having a glass transition temperature of preferably 60 ° C. or higher, and usually 70 ° C. to 100 ° C. as the adhesive 105, a situation in which the reinforcing effect cannot be obtained by irradiation with sunlight. It is possible to avoid this, obtain a sufficient reinforcing effect, and avoid peeling of the fiber sheet from the surface of the steel structure before reaching the breaking strength.

  Examples of the adhesive having such characteristics include room temperature curable epoxy resins, epoxy acrylate resins, acrylic resins, MMA resins, vinyl ester resins, unsaturated polyester resins, photocurable resins, and the like. Room temperature curable epoxy resins and MMA resins are preferred.

In this example, an epoxy resin adhesive was used. The epoxy resin adhesive is provided by a two-component type of a main agent and a curing agent, and an example of the composition is as follows.
(I) Main agent: An epoxy resin is used as a main component, and a material containing a silane coupling agent as necessary is used as an adhesion enhancing agent. The epoxy resin can be, for example, a bisphenol type epoxy resin, in particular, a rubber-modified epoxy resin for imparting toughness, and a reactive diluent and a thixotropic agent may be added depending on the application.
(Ii) Curing agent: containing amines as a main component, optionally containing a curing accelerator and using a colorant or the like as an additive, the main component epoxy resin: the amine equivalent ratio of the curing agent is Each is 1: 1. The amines can be aliphatic amines including, for example, metaxylene diamine and isophorone diamine. The epoxy resin having such a composition has a glass transition temperature of 70 ° C. or higher (74 ° C.).

  Although the adhesive 105 has been described as being applied on the elastic layer 104, it can of course be applied to the fiber sheet 1, and on both the surface of the elastic layer 104 and the adhesive surface of the fiber sheet 1. It may be applied.

  Moreover, when there is much required reinforcement amount, it is possible to adhere | attach the multiple layers fiber sheet 1 on the structure surface. However, if the fiber sheets 1 having a plurality of layers are laminated and bonded, stress concentration occurs at the end portion, and the peel fracture resistance may decrease.

  Therefore, in order to prevent peeling failure, it is preferable to change the sheet length (L) (see FIG. 1) of the fiber sheet 1 of each layer as shown in FIG. For example, the length of the fiber sheet 1 to be laminated in a plurality of layers is shortened in order as it goes to the outer layer that is separated from the structure surface 102, and the end portions 1a of the fiber sheet 1 are laminated stepwise. The shifting length (h) of the end 1a is suitably about 30 mm to 300 mm. For example, good results could be obtained by bonding the sheet end 1a so as to be shortened by 100 mm.

  That is, by reducing the length (L) of the fiber sheet 1 to be laminated in a plurality of layers by reducing the outer layer by about 30 to 300 mm in order and laminating the end 1a in a stepped manner, the stress concentration at the sheet end 1a is reduced, It is possible to improve the peeling resistance.

Next, the following experiment was conducted to demonstrate the effect of the reinforcing method及beauty steel structure reinforcing elastic layer forming material of the structure according to the present invention.

Experimental example 1
In this experimental example, the fiber sheet 1 was used to reinforce the steel material as the steel structure 100 according to the bonding method. Moreover, the fiber sheet 1 used in this experimental example was the fiber sheet 1A having the configuration described as the specific example 1 with reference to FIG.

As the reinforcing fiber f in the fiber sheet 1A, pitch-based carbon fiber strands with an average diameter of 10 μm and a convergent number of 6000 resin-impregnated pitch-based carbon fiber strands were aligned in one direction so as to have a fiber basis weight of 300 g / m ² to form a sheet. A biaxial mesh-like support 3 made using glass fiber was welded to one side of the sheet-like reinforcing fiber to obtain a fiber sheet 1A.

  The fiber sheet 1 made as the fiber sheet 1A thus produced had a width (W) of 500 mm and a length (L) of 50 m. In this example, such a fiber sheet was appropriately cut out and used.

  Next, the steel material 100 as a steel structure using the fiber sheet 1 was reinforced by the same fiber sheet bonding method as described with reference to FIG. However, in this experimental example, the fiber sheet 1 was attached to the lower surface side of the steel material 100.

First, in this experimental example, the lower surface of the steel material 100 was polished by shot blasting to obtain an appropriate rough surface. 0.15 kg / m ² of epoxy-modified urethane primer (“FORCAUL-1” (trade name) manufactured by Nippon Steel Materials Co., Ltd.) 103 was applied onto the surface 102 of the steel material 100.

  After the epoxy-modified urethane resin primer 103 is dry to the touch, the polyurea resin putty having the above-described composition is formed with a thickness (T) of about 1 mm in order to form the elastic layer 104 with the application surface as the back surface. The steel material (specimen) 100 was applied with a spatula. At this time, the polyurea resin putty agent was not dripped by its own weight even after the application was completed, and adhered to the steel specimen 100.

  The putty-like polyurea resin used as the resin for forming the elastic layer 104 had a viscosity of 600 Pa · s at 2 revolutions by a BM viscometer at 23 ° C. and 95 Pa · s at 20 revolutions.

  The thixotropic index (viscosity at 20 revolutions ÷ viscosity at 2 revolutions) was 6.32.

Next, the polyurea resin putty agent applied to the steel surface 102 was cured to form an elastic layer 104. On this elastic layer 104, an epoxy resin having a glass transition temperature of 74 ° C. as described above is applied at a coating amount of 0.4 kg / m ² (as an undercoat for each layer when a plurality of fiber sheets 1 are laminated). It was attached. Next, after lightly pressing the fiber sheet 1 against the epoxy resin coated surface, a plastic roller having a width of 100 mm and a diameter of 10 mm was moved on the fiber sheet 1 while applying a pressing force of about 100 N. The fiber sheet was formed by laminating a total of 7 layers of the above-described fiber sheets with an adhesive. Specifically, five layers of “Carbon Fiber Sheet C830” (trade name) manufactured by Nippon Steel Materials Co., Ltd., and “Carbon Fiber Sheet C160” (trade name) of Nippon Steel Materials Co., Ltd.) Two layers were laminated.

  By rolling from the sheet 1 with a plastic roller, the epoxy resin has exuded from the gaps between the fibers of the fiber sheet 1 and is peeled off while being stuck to the steel material 100 without any holding. I never did.

In the case of laminating a plurality of fiber sheets 1 as in this embodiment, an epoxy resin 105 is applied to the surface of the fiber sheet 1 at a coating amount of 0.2 kg / m ² as a top coat for each layer. To finish the surface flat. Thereafter, it was cured at room temperature for 1 week. It was possible to adhere to the steel material 100 very well without generating any voids on the sticking surface of the fiber sheet 1.

  The fiber sheet reinforced steel material (invention) 100 produced as described above, an epoxy resin impregnated adhesive having a glass transition temperature of 48 ° C. as an adhesive, and a polyurethane resin putty agent (comparative example) as a putty agent The fiber sheet reinforced steel material 100 using 1) and the soft epoxy resin putty agent (Comparative Example 2) was subjected to a three-point bending test with a fulcrum distance Ls of 80 mm using the test apparatus shown in FIG. . The cross section of the steel material 100 has a width W0 = 25 mm, a thickness T0 = 2.0 mm, and a total length L0 = 100 mm. As described above, the three specimens were made with the same structure and materials except that the adhesive 105 and the putty agent 104 for bonding the fiber sheet to the steel surface were different.

  The constituent materials of the present invention and Comparative Examples 1 and 2 in this experiment are summarized in Table 3 below.

  The results of the bending test are shown in FIGS. The following is noted from the bending test graph with the temperature / load varied as shown in FIG.

  In other words, in the specification of Comparative Example 1, the load decreased near 30 ° C., and the epoxy resin-impregnated adhesive softened. On the other hand, taking advantage of the properties of epoxy resin that hardens at low temperatures, it showed a high load. In this situation, Japan's climatic conditions and repair and reinforcement performance cannot be satisfied on the high temperature side.

  In the specification of Comparative Example 2, the soft epoxy resin putty agent hardened with the temperature at a low temperature, and reached early peeling before the load increased. This indicates a situation where reinforcement is not possible. On the high temperature side, peeling occurred due to early material destruction of the soft epoxy resin putty.

  On the other hand, it was confirmed that the polyurea resin putty agent of the present invention showed stable performance from low temperature to high temperature, and that repair and reinforcing materials and construction method specifications that meet Japanese national weather conditions were established.

Experimental example 2
In this experimental example, the same fiber sheet 1 as described in Experimental Example 1 was used, and the steel material as the steel structure 100 was reinforced in accordance with the bonding method.

  That is, in the fiber sheet reinforced steel material (present invention) 100 of the present invention, the fiber sheet 1 produced as described above was prepared by using a urethane-modified epoxy resin primer as the primer 103 and the elastic layer 104 as in the above Experimental Example 1. As a putty agent, a polyurea resin putty agent having the above composition was attached to the steel material 100 using an epoxy resin having a glass transition temperature of 74 ° C. as the adhesive 105.

  In Comparative Example 3, the fiber sheet 1 produced as described above uses an epoxy resin primer as the primer 103, does not use a putty agent for the elastic layer 104, and the adhesive 105 has a glass transition point. The epoxy resin having the above composition at a temperature of 74 ° C. was used to attach the steel material 100.

  In Comparative Example 4, the fiber sheet 1 produced as described above was used in the same manner as in Experimental Example 1, and an epoxy-modified urethane resin primer was used as the primer 103, and polyurea was used as a putty agent for the elastic layer 104. A resin putty agent was used, but an epoxy resin (“FR-E3P” (trade name) manufactured by Nippon Steel Materials Co., Ltd.) having a glass transition temperature of 48 ° C. was used as an adhesive.

  Using the three specimens produced as described above, the same bending test as in Experimental Example 1 was performed. The test results are shown in Table 4 and FIG.

  The following can be understood from the bending test graph with the temperature / load varied as shown in FIG.

  In Comparative Example 3, an epoxy resin adhesive having a high Tg such as a glass transition temperature of 74 ° C. is used as an adhesive as in the present invention, but the fiber sheet 1 is stuck to the steel material 100 without using a polyurea resin putty agent. ing. Therefore, compared with the present invention, in Comparative Example 3, the effect of the polyurea resin putty agent (elastic layer 104) cannot be obtained, and sufficient reinforcement of the steel material is not achieved with an increase in temperature. In Comparative Example 3, the epoxy resin adhesive was finally peeled off as in Comparative Example 2.

  In Comparative Example 4, a polyurea resin putty was used as in the present invention, but a comparatively low Tg epoxy resin adhesive having a glass transition temperature of 48 ° C. was used as an adhesive. In this case as well, the fiber sheet layer 106 is not peeled off due to the effect of the polyurea resin putty agent (elastic layer 104) as in the present invention, but gently bent from a glass transition temperature of around 48 ° C. The load decreases, and the reinforcement itself is not sufficiently achieved at a high temperature as compared with the present invention. In other words, Comparative Example 4 shows a situation where the fiber sheet layer 106 using carbon fiber is bent together with the steel material. Therefore, in order to obtain a reinforcing effect even at high temperatures, it is necessary to adjust the glass transition point of the adhesive, and the glass transition point of the adhesive is 60 ° C. or higher in order to cope with the temperature necessary for the climatic conditions. It is necessary that the temperature be 70 ° C. or higher.

Thus, according to the reinforcing side Ho及 beauty steel structures reinforcing the elastic layer forming material of steel structures in accordance with the present invention, it was revealed that effectively reinforce the steel structure 100.

DESCRIPTION OF SYMBOLS 1 Fiber sheet 2 Fiber reinforced plastic wire 3 Wire material fixing material (weft, mesh support sheet, flexible strip)
DESCRIPTION OF SYMBOLS 100 Steel structure 103 Primer 104 Elastic layer 105 Adhesive 106 Fiber sheet layer 200 Reinforcing structure

Claims (8)

In a method for reinforcing a steel structure in which a fiber sheet containing reinforcing fibers is bonded and integrated on the surface of the steel structure,
(A) applying a polyurea resin putty agent to the surface of the steel structure and curing it to form an elastic layer;
(B) the said fiber sheet to the surface of the steel structures elastic layer is formed, possess a step of bonding, a by an adhesive,
The polyurea resin putty agent has a tensile elongation at curing of 400% or more, a tensile strength of 8 N / mm ² or more, and a tensile modulus of 60 N / mm ² or more and 500 N / mm ² or less,
The adhesive has a glass transition temperature of 60 ° C. or higher.
A method for reinforcing a steel structure, characterized in that: Before Kise' Chakuzai is claimed in claim 1, wherein cold-setting epoxy resin, epoxy acrylate resin, an acrylic resin, MMA resin, vinyl ester resin, unsaturated polyester resin, or, that it is a photocurable resin Steel structure reinforcement method. Before forming the elastic layer on the surface of the steel structure, according to claim 1 or 2, characterized in that a step, of applying the process and / or primers surface treatment of the surface of the steel structures Steel structure reinforcement method. The steel sheet according to any one of claims 1 to 3 , wherein the fiber sheet is a fiber sheet in which continuous reinforcing fibers aligned in one direction are fixed to each other with a wire rod fixing material. Reinforcement method. The fiber sheet is a fiber sheet in which reinforced fibers are impregnated with a matrix resin, and a plurality of cured continuous fiber reinforced plastic wires are aligned in a slender shape in the longitudinal direction, and the wires are fixed to each other by a wire fixing material. The method for reinforcing a steel structure according to any one of claims 1 to 3 , wherein: The fiber sheet, the resin is impregnated into a continuous reinforcing fiber sheet was aligned in one direction, the resin is as claimed in any one of claims 1-3, characterized in that the fiber sheet is cured A method of reinforcing steel structures. The steel structure according to any one of claims 1 to 6 , wherein the fiber sheet is laminated and bonded to the surface of the steel structure in a plurality of layers, and is integrated with the steel structure. How to reinforce things. A method of reinforcing a steel structure in which a fiber sheet containing reinforcing fibers is bonded and integrated on the surface of the steel structure,
(A) applying a polyurea resin putty agent to the surface of the steel structure and curing it to form an elastic layer;
(B) bonding the fiber sheet to the surface of the steel structure on which the elastic layer is formed, using an adhesive;
A steel structures reinforcing the elastic layer forming material made of polyurea resin putty agent to form a pre-Symbol elastic layer Te reinforcing method smell steel structures having,
The polyurea resin putty agent has a tensile elongation at curing of 400% or more, a tensile strength of 8 N / mm ² or more, and a tensile modulus of 60 N / mm ² or more and 500 N / mm ² or less. Elastic layer forming material for reinforcement.

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